Hypervideo is a displayed video stream that includes user selectable anchors, referred to as “hotspots,” that are linked to ancillary information. When a user views a hypervideo clip and selects the hotspot, the user can navigate from the video clip to the linked ancillary information. For example, a hotspot can be associated with an element in the video clip, such as a red automobile, and when selected, additional information about the automobile can be presented to the user, or a different video clip or a different segment of the same clip can be shown to the user.
In order to associate hotspots with elements in a hypervideo stream, it is necessary to track the position of the individual elements within the video clips used. Thus, when the exemplary red automobile is moving, the hypervideo media player system must be able to determine when the hotspot associated with the automobile has been selected, regardless of where it is on the screen when the selection is made. For video clips created artificially, e.g., by computer graphics, element tracking is relatively simple because the position of an element is specified on a coordinate system and that information can be then used to track the element. For video clips created from or based on live footage, however, element tracking is more complex. The video clip comprises a plurality of video frames, where each frame represents a still picture or “snapshot” of a particular moment in time. While each video frame contains visual information sufficient to permit the human brain to distinguish individual elements, such visual information does not generally enable a computer system to recognize the elements.
Nevertheless, several hypervideo authoring systems have been developed that support element tracking through the generation of hotspots that move with the element. FIGS. 1A, 1B and 1C illustrate three (3) exemplary video frames, 10A, 10B, and 10C, of a hypervideo stream that includes moving elements. In FIG. 1A, the first video frame 10A includes a first element, e.g., an automobile, that is associated with a first hotspot 12A. As is shown, the first hotspot 12A can be a defined region, referred to as an activation region, that can be similar in shape and size to the first element with which it is associated.
For the sake of clarity, the first hotspot 12A is represented by a rectangular box that generally encompasses the first element. In other instances, the defined region of a hotspot associated with an element is not displayed to the user. Rather, the appearance of a cursor 100, or any pointer indication, can change when the cursor 100 position is within the activation region of a hotspot. For example, when the cursor 100 is within a hotspot, the cursor 100 can appear as a pointing finger, otherwise the cursor 100 can appear as an arrow. Typically, when a viewer places the cursor 100 over the first element and selects the first element, the viewer effectively activates the associated first hotspot 12A. In this example, when the first hotspot 12A is activated, information 14A about the first element associated with the first hotspot 12A is presented.
In FIG. 1B, the second video frame 10b includes the first element and a second element, the rear automobile, that is also associated with a second hotspot 12b. As is shown, the first hotspot 12A is in a different location and has a different shape/size because the first hotspot 12A is tracking the location and shape/size of the first element. Generally, because the first element is “moving” away from the camera, its relative size is decreasing and thus, the size of the first hotspot 12A is also decreasing. As the size of the hotspot 12A decreases with each successive video frame (assuming the first element continues to travel away from the camera), it can be increasingly difficult for the viewer to place the cursor 100 on the first element to activate the associated first hotspot 12A. Thus, in FIG. 1C, while the viewer has placed the cursor 100 near the first element and selected what the viewer thinks is the first element, the cursor placement and selection actually has activated the second hotspot 12B, which is associated with the second element. As a result, information 14b about the second element associated with the second hotspot 12B is presented.
For some users, positioning the cursor 100 over a stationary graphical display element, such as an icon or hypertext link, can be difficult. In some instances, a user may exhibit diminished visual or physical abilities, or lack training and practice to correctly position the cursor 100. This difficulty is exacerbated in a hypervideo stream because elements captured in video clips, and their associated hotspots, are typically moving, and even if the element itself is physically stationary, the camera may be panning or zooming, thereby resulting in perceived movement.
Moreover, difficulties in positioning the cursor 100 properly can be attributable to the computer system itself. For example, a computer display can provide a high density presentation of material, rendering graphical display elements relatively small. Similarly, small computer displays, such as those for palm-held devices, may make graphical display elements difficult to select. In addition to user abilities and hardware limitations, the content displayed may include small elements, such as jewelry, with correspondingly small hotspots, making user selection with a pointing device difficult.
As illustrated above, inaccurate cursor positioning can result in mistakenly activating a hotspot associated with another element. With hypervideos, this mistake is particularly frustrating because the video stream continues for a specified time. To correct the mistake, the user must either replay the video clip or stop the presentation of the video clip and/or rewind it to some point. Moreover, the mistakenly activated hotspot can produce completely unintended results, which can be detrimental to the user. For example, in FIG. 1C, the viewer can mistakenly believe that he is reading information 14B about the front automobile, when in fact, the information 14B pertains to the rear automobile.
Accordingly, there exists a need for methods, systems, and computer program products for helping a user to track and activate a hotspot associated with an element in a hypervideo.